DISTRIBUTION OF CENTRAL CORNEAL THICKNESS AND ITS ASSOCIATION WITH INTRAOCULAR-PRESSURE - THE ROTTERDAM STUDY

PURPOSE: To perform a cross-sectional study on the distribution of cen tral corneal thickness and its association with intraocular pressure i n an elderly population. METHODS: We measured central corneal thicknes s and intraocular pressure in 395 subjects (352 control subjects, 13 p atients with ocular hypertension, and 30 patients with primary open-an gle glaucoma) aged 55 years or more. RESULTS: Mean central corneal thi ckness in the 352 control subjects was 537.4 mu m (95% confidence inte rval [CI], 533.8 to 540.9 mu m; range, 427 to 620 mu m), with a maxima l difference between eyes of 42 mu m. There were no differences betwee n sexes and no significant association with age, Linear regression ana lysis showed an increase of 0.19 mm Hg in intraocular pressure with ea ch 10-mu m increase in central corneal thickness (95% CI, 0.09 to 0.28 mm Hg), This association was similar in both eyes and in both sexes. The 13 patients with ocular hypertension had corneas a mean of 16.0 mu m thicker (95% CI, -2.6 to +34.6 mu m) compared with control subjects (P = .093); the 30 patients with primary open-angle glaucoma had corn eas a mean of 21.5 mu m thinner (95% CI, 8.8 to 34.1 mu m) compared wi th control subjects (P = .001). CONCLUSION: Mean central corneal thick ness was similar to that found in clinical studies, was slightly highe r in patients with ocular hypertension, and was significantly lower in patients with primary open-angle glaucoma, Intraocular pressure was p ositively related with central corneal thickness, Central corneal thic kness may influence the division between normal and increased intraocu lar pressure at a simple cutoff point of 21 mm Hg.